Good day Looking for some advice. I am using a UHF MastrII repeater as an extra receive site that is outside mounted in an outdoor GE cabinet. The receiver is 449.4500 and CG 114.8 on a Stationmaster antenna at 215 feet, and transmit out is 420 at 10 watts into a yagi at 50 feet. I am using ½" Andrew heliax for both antennas. The antennas are on a FM digital broadcast tower on 106.3 MHz transmitting around 3kW of power (if my memory is correct) antenna at 400 feet. This site has been in service for a couple of months, and has worked flawlessly. After a thunderstorm went through Friday night with some heavy rain the repeater started keying up on its own as if it was being kerchunked. It acts like it is hearing an input signal to repeat, but at times the transmit relay just clatters and never actually drives the PA enough to reach to the main site. It almost acts like the squelch setting is just a tad too low causing the clatter, however I have found this is not the case. On a couple of occasions the repeater just keys and stays keyed for a second or two. I checked using an IFR monitor the input frequency to see if something was being heard and nothing was found when this clattering occurs. I also removed the receive antenna to see if something was being heard locally and the issue occurred while the antenna was off. The kerchunking occurs even if the CG board (factory dip switch style) is in or out. This repeater is very basic; I am using the GE factory repeater control card, repeater audio, and 10-volt regulator cards. Voltage was checked from the factory power supply to have input of 121.8 VAC with output at 14.9 VDC, and 10.04 VDC from the 10-volt regulator card. At first I was suspecting a possible problem with the delay timer on the repeater control card, however it is set to drop as soon as carrier received signal drops. I traced the RUS voltage at several different locations and it seems to be acting, as it should like it is hearing a signal. I had some spare parts along so I tried a couple of things with no change or correction to the problem. A different CG board (dip switch style) was installed, no change, even tried a different PL. A spare receiver was installed, no change. 10-volt regulator was swapped out, no change. Tried adjusting power level on PA, no change. We used a site master to check the feed lines, both antennas and everything looks good. Everything in the cabinet is dry with no sign of water. Has anyone encountered a similar problem? I don't see anything from the FM station on Spectrum Analyzer, but could it be interference? Anyone have experience with radio station sites? I am going to pull the unit and bring it home for a few days to see what happens. Someone suggested as a wild guess, an intermittent electrolytic capacitor.
Ideas?
